Sinker-head structure for knitting machines



G. BITZER SINKER-HEAD STRUCTURE FOR KNITTING MACHINES Filed 001'.. 19, 1956 FJ. E- J 1%/1 /Tllll/ April 5, 1960 IN V EN TOR. 'olab Bi r BY ATTORNEY.

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MACILHNES Application october 19, i955, serai No. @7,078 s claims. (er. ss- 110) This invention relates to sinker-head structure for straight bar knitting machines and more particularly to a sinker-head structure having metallic and non-metallic portions and to the method of attaching such metallic and non-metallic portions to each other.

In Straight bar or full-fashioned knitting machines the base and cap members of the sinker-head are usually constructed of `brass and are provided with aligned slots for guiding steel sinkers and dividers in their movements during formation of fabric loops. The base member also has a front or presser edge portion against which steel needles are pressed to close the beards thereof in the usual manner. Normally the brass of the sinker-head parts is an ideal bearing material for the steel material of the sinkers, dividers and needles. However, at present, due in part to an increase in the operating speed of these parts, which causes additional and unforeseen operating stresses, and in part from conditions arising from the almost exclusive use of synthetic yarns in the knitting processes, it has been found that wear rapidly develops not only in the slots and presser edge, but also in the needle beards. Unless the worn sinker-heads are discarded and replaced -by new heads such wear causes malfunctioning of the parts in forming the loops of the fabric and damage to the yarns which results in the production of fabrics unsightly in appearance and defective in construction.

In order to avoid the frequent discarding of worn sinker-heads, it has been proposed to recondition the sink-heads by removing the worn slotted portions of the base and cap members and replacing these worn portions with inserts of the same or a diierent material. However, -while the reconditioning of the original sinkerheads saves some of the cost of replacing the entire sinker-head no metallic or non-metallic material was heretofore proposed for this purpose that solved the wear problems or which did not present difculties in machining the inserts and in securing them to the original sinkerhead parts.

It is an object of the invention to provide a sinkerhead structure for a full-fashioned knitting machine with inserted bearing portions for the sinkers, dividers and needles, and to provide a method of attaching such portions, which will eliminate the above noted and other defects of prior proposals.

Another object of the invention is to provide a metallic sinker-head structure with inserted bearing portions for the sinkers, dividers and needles of a synthetic material of the so-called nylon type which has greater resistance to wear than the metallic portions of the sinker-head.

A further object of the invention is to provide a metallic sinker-head structure with replaceable bearing portions of synthetic material and to the provision of an adhesive material for securely bonding the metallic and synthetic materials of the sinker-head and bearing portions to each other.

With these and other objects in view, which will become apparent from the following detailed description of the illustrative and practical embodiments of the invention shown in the accompanying drawings, the invention comprises the novel method steps, elements, features of construction and combination of parts in cooperative relationship, as hereinafter more particularly pointed out in the claims.

In the drawings- Figure l is a cross-sectional view taken through a sinker-head for a full-fashioned knitting machine having replaceable inserts incorporated therein in accordance with the instant invention;

Fig. 2 is a perspective view of the cap member of the sinker-head;

Fig. 3 is a perspective view of the base member of the sinker-head; and

Fig. 4 is a View on a reduced scale similar to a portion of the einiger-head of Fig. l, showing a modified form of replaceable inserts according to the invention.

A sinker-head structure according to the invention comprises rigid cap and base members of metal, and nonmetallic inserted bearing portions providing the means for guiding the sinkers and dividers and for closing the Ibeards ofthe needles during the usual knitting movements of these elements. The nonmetallic and metallic portions of the sinker-head are joined or bonded to each other -by a bonding agent or adhesive that not only resists deterioration due to contact with the various liquids used in lubricating and cleaning the sinker-head but also resists separation of the parts dueto the difference in expansion and construction of the metallic and non-metallic materials occasioned by temperature changes in the parts.

Referring to Fig. l of the drawing, there is shown a portion of the loop forming or knitting head of a full- `fashioned knitting machine including one of -a row of bearded needles 1G, a knockover bit l1 mountedV in a bed l2, sinkers i5 and .dividers `16, the sinkers and dividers alternating with each other along the width of the knitting head. The sinkers l5 and dividers 16 are mounted for sliding movement between the needles 10 in a base member i7 and a cap member 20 of a sinker-head structure 21. The sinkers l5 and dividers lr6 are guided for sliding movement in lower slots Z2 formed in the base member 17 and in upper slots ZS in the cap member 20. The sinkers l5 and dividers 16 are advanced and retracted in the slots and the needles 10 are given combined vertical and horizontal movements to engage and close the beards thereof against a front or presser edge portion 26 of the base member -by conventional means (not shown) to form yarns into loops in a usual manner.

ln the usual practice the base member 17 and cap member 2G are made throughout of a non-ferrous metal such as brass which normally provides the most desirable bearing material for the movement of the sinkers l15 and dividers 16 which are made of steel. However, wear occurs in the bottom of the slots for the dividers 16 and particularly at the ends thereof which is believed to be caused by adverse stresses set up in the dividers during their high speed movements and/or deterioration of the brass material caused by chemical action of the various iluids used to lubricate and cleanse the sinker-head. Wear also occurs in the presser edge where it is contacted by the beards of the needles lll which is the result of not only the action of the fluids used on the sinker-head but also the abrasive action of the sizing deposited on the beards of the needles -by the yarns. When the wear in the slots and the presser edge becomes excessive to the point that defective loops are produced, which usually occurs in a very short time, the sinker-head must be discarded and replaced by a new sinker-head or be reconditioned.

In order to greatly increase the ywearing life of the slotted portions of the sinker'heads and to avoid discarding the entire sinker-heads when worn, according t0 the invention the slotted portions of the base and cap members are formed as replaceable inserts. As shown in Figs. 1 and 3, the base member 17 has a recess 27 formed therein to receive an insert 39 which is .secured to the base member by a layer 31 of adhesive or the like. The cap member 2% is also provided with a recess 32 to receive an insert 35 which is secured to the cap member by a layer 36 of adhesive (Figs. 1 and 2). The inserts 30 and 35 are machined to the desired shape and are slotted to receive the sinkers and dividers preferably after 'they have been secured to the base and cap members respectively. The recesses 27 and 32 may be initially formed in the base Aand cap members 17 and 20, respectively, of new sinker-heads, or in the case of used sinker-heads, may be formed when a worn sinker-head is reconditioned.

Preferably the inserts 30 and 35 cover the entire length land width of the slotted portions in the base and cap members 17 and 20 respectively (Figs. 1, 2 and 3). However, in a modiiied form, the inserts while extending along the entire length of the slotted portion of the base and cap members, may only extend across a portion or portions of the width of these parts and particularly adjacent the opposite longitudinal edges where the greatest wear occurs. As shown in IFig. 4, which illustrates this modification, the base member 17 is provided with 4*forward and rear recesses 40 and 41, respectively, for vthe reception of front and rear partial inserts 42 and 45, respectively. The cap member 20 is provided with forward and rear recesses 46 and 47, respectively, for the reception of front and rear partial inserts 56 and 51, respectively. In this modication the partial inserts -are secured in their respective recesses by a layer 52 of adhesive. Following the cementing of the partial inserts in the base and cap members 17 and 20 of the sinkerhead 21, slots for the sinkers 1'5 and dividers 16 are formed in the inserts matching the slots in the metallic portions remaining in the base and cap members.

The inserts 30 and 35 and the partial inserts 42, 4S, 50 yand 51 are made of a material such as a synthetic linear condensation polymer of the type generally referred to as nylon or other known composition having similar properties. The nylon not only resists the wear caused by the sinkers 1'5, Idividers 16 and needles 1.0 as hereinbefore set forth, but also is impervious or substantially impervious to the chemical action of the various solutions to which the sinker-head is subjected.

The cement employed for the layers 31, 36 and S2 is of a type that is thermosetting and that will adhere or bond itself to both the metal of the base and cap members and to the synthetic material of the inserts 39 and 35 and the partial inserts 42, 45, 50 and 51. ln the carrying out of the instant invention the cementing llayer that was found to give the most desirable results was composed of two well known commercial adhesives, Cycleweld which is compounded of phenol-formaldehyde and a synthetic rubber such as Buna N made by Chrysler Corp. and Cascophen No. RS-216 which is a resorcinol-phenol compound made by The Borden Co.

In preparing the parts for jointure, the surface of the insert to be joined to the metallic member is machined to remove the outer skin and the contact surfaces of both the metal member and the nylon insert are slightly roughened as by shot blasting and thoroughly cleaned of all dirt and grease. The metal surface is primed or coated with the Cycleweld compound which is permitted to air dry for approximately 15 minutes and then baked at 300 degrees for approximately 15 minutes to remove all solvent. A coating of Cascophen is then applied over the coating of Cycleweld `and the surface of the insert and the Cascophen coating is allowed to air dry for approximately minutes after which the insert is assembled with and clamped to the metal member for approximately 10 hours at room temperature. The assembled parts are permitted to cure for 2 to 3 days' at which time the cement is completely set and reaches its maximum shear strength. The `faces of the inserts are then machined to correspond to the adjoining faces of the metal parts and slotted and the sinker-head parts assembled in the usual manner and placed in the knitting machine.

As distinguished -from prior proposals, the instant invention provides a sinker-head structure applicable to both new and reconditioned machines having a much longer working life than heretofore obtained. The method employed for bonding the non-metallic inserts to the metallic members insures against separation of the parts under the rigorous condition of operation of the machine.

Hav-ing described my invention in full detail, it will bev understood that these details need not be strictly adhered to and that various changes and modiications may be made falling within the scope of the invention as deiined bythe following claims.

=I claiml. A sinker-head structure for a straight bar knitting machine having a slotted section for slidably mounting sinkers and dividers, said sinker-head structure comprising portions of brass, non-metallic portions of a material comprising a synthetic linear condensation polymer, said last mentioned portions extending the length of said slotted section,A and a thermosetting adhesive bonding said metallic and non-metallic portions to each other, said adhesive including a compound of resorcinol-phenol.

2. A sinker-head structure for a straight bar knitting machine having a slotted section for slidably mounting sinkers and dividers, said sinker-head structure comprising portions of brass, non-metallic portions of a material comprising ya synthetic linear condensation polymer, said last mentioned portions extending the length of said slotted section, and a thermosetting adhesive bonding said metallic and non-metallic portions to each other, said adhesive including a compound of phenol-formaldehyde modified by synthetic rubber and a compound of resorcinol-phenol.

3. In the manufacture of a sinker-head structure for a straight bar knitting machine having a slotted section for slidably mounting sinkers and dividers, said sinkerhead structure including a portion of brass and a nonmetallic portion of a material comprising synthetic linear condensation polymer, said last mentioned portion extending the length of said slotted section, the method of bonding said metallic and non-metallic portions to each other comprising the steps of coating the surface of said metallic portion to be contacted by said nonmetallic portion with an adhesive primer comprising phenol-formaldehyde modiiied 'by synthetic rubber land a solvent, drying said adhesive primer to remove the solv ent, coating said adhesive coating on said metallic portion and the surface of said non-metallic portion to be contacted by said metallic portion with an adhesive consisting of resorcinol-phenol, joining and clamping the contact surfaces of said metallic and non-metallic portions to each other, and ydrying and setting said adhesive at room temperature.

References Cited in the tile of this patent UNITED'STATES PATENTS 2,376,854 Saunders May 22, 1945 2,384,451 Brumbach Sept. 1l, 1945 2,385,371 Rhodes Sept. 25, 1945 2,399,184 Heckert Apr. 30, 1946 2,422,479 Golaszewski et al June 17, 1947 2,426,803 Weisbecker Sept. 2, 1947 2,479,342 Gibbons et al Aug. 16, 1949 2,675,276 Daugherty Apr. 13, 1954 2,710,528 Cobert June 14, 1955 QM... mi 

